Filip Urban played qualies and semifinals and finals at the same time in Poland this year :P Plus, he had to travel between two cities to do that So, I'd say it's possible :P

yeee... and the distance was abour 300 km !!!
he said he was driving like crazy it was so evident on the court but they won doubles in the challenger (as i remember ) and he nearly got into MD (choked few balls in the last set)